Ever longed for a simple way to type a mathematical expression in HTML just to realize there is no proper way for doing that? There is: MathJax (Thanks to JavaScript). All you have to do is to insert the following sniplet into the head of your html file.

<script type="text/javascript"

Here’s an example of the Lorenz attractor (taken from the MathJax Demo page): \begin{align} \dot{x} & = \sigma(y-x)
\dot{y} & = \rho x - y - xz
\dot{z} & = -\beta z + xy \end{align}

The source:

\dot{x} &= \sigma(y-x) \\
\dot{y} &= \rho x - y - xz \\
\dot{z} &= -\beta z + xy

You probably have to escape the two backslash characters \\ (the newline command). Works also for inline expressions like this $e^{\imath \pi} + 1 = 0$.